There are countless brands of plastics … that offer countless plastics … Here I give you the fruit of my experience.
What is PLA?
PLA plastic or Polylactic acid (Polylactic acid) is a plastic of vegetable origin, bio-degradable. It is the most commonly used material in 3D printing because it is inexpensive and easy to use.
Attention, yes it is bio-degradable, but only in industrial composting, i.e. under high heat. In practice, I haven’t yet found a solution to recycle it. I’m waiting for the end of the confinement to go and ask at the waste collection centre in my town to see if they’ll take it back.
On the other hand, you have to be aware that the plastic you use is composed of PLA…and many additives.
Finally, it is theoretically possible to crush the scraps and rejects and melt them into a new filament. Unfortunately, there are only a few companies carrying out this operation because :
- risk of damaging the recycler if a metal part is among the PLA scraps
- economically unattractive: 1kg of PLA on Amazon costs around 20€. The return trip of 1kg by colissimo costs around 16€ .
PLA or ABS ?
ABS has many advantages in terms of strength and temperature resistance. However, it is more difficult to print because it requires higher temperatures. It is derived from petroleum, and gives off harmful vapours during printing. For all these reasons, I have never tried it, PLA being sufficient in all cases.
Which PLA ?
And this is what interests us most: which PLA to buy. Personally, I always buy from Amazon, especially because they deliver quickly.
For a long time I ordered the cheapest PLAs I could find for two reasons:
- It’s the cheapest
- If a low-end PLA allows me to carry out my projects, it’s the assurance that everyone will be able to do the same with any plastic.
Indeed, if I make a pedal, but it only holds up if I use a top-of-the-range PLA, which is hard to find and expensive, it doesn’t make my projects accessible.
Various specialised sites also offer PLA at very interesting prices, sometimes cheaper than Amazon.
Before buying in quantity, or buying several colours at once, be aware that :
- PLA dries over time and becomes brittle. A spool that has been out of its packaging for 3 months will become brittle: in particular, the thread will break at the extruder if the bend is too steep.
- PLA switches are always a risk of machine malfunction.
1kg, 2kg, 3kg?
The quantity of plastic is an important factor when purchasing. Unless you want to make a specific print with a specific colour, 0.5kg rolls should be avoided.
Indeed, the smaller the spool, the quicker you will ask yourself the question: is there enough PLA left to start a print? You will then have to monitor the printing more frequently, which may be possible during the day, but impossible at night… unless you wake up in the middle of the night…
So ideally, you will prefer spools of one kilo…or even more? Maybe not, as indicated above, PLA dries so you shouldn’t buy 3kg of PLA all at once, and then let 2kg dry…
PLA+ is a PLA…better! There is no specific standard that controls the appellation, and I have only tried two references, to which I have been faithful ever since. See for yourself the print quality (0.2 resolution):
50€ per 2.5kg on Amazon. Some might argue that the print quality of this plastic is a consequence of the printer setting, and that the same quality can be obtained with a cheaper PLA by perfectly adjusting your printer. Perhaps. It’s just my experience.